A myriad of exercise machines are on the market today. These machines are used to simulate a wide variety of exercise motions, and may be used for a range of physical training regimens, including, for example, resistance training and aerobic endurance training. Machines may be purchased for simulating weight lifting motions, running motions, stair-climbing motions, skiing motions, cycling motions, walking motions, and others. A particular advantage of many of these machines is the reduction of the bodily impacts associated with many exercise activities. Cycling simulators, ski simulators, and stair simulators may be particularly noted for the elimination of impacts affecting the hips, knees, ankles, and feet. These machines generally do not reproduce what to many are the most natural exercise motions: walking and running.
Most currently available exercise machines for simulating walking and/or running are treadmill-type devices. While these machines allow walking and/or running exercise motions while remaining stationary, treadmills do not reduce or eliminate impacts inflicted on the user's lower limbs. There exists, therefore, a need for an exercise machine which simulates a natural running motion while eliminating the impacts on the user normally associated with walking and/or running. Previous devices producing low- or no-impact leg motions often produce unnatural reciprocating-type motions of the feet, and do not produce an orbital-type motions of the feet normally associated with running and/or walking. In addition, the ankle flexion normally associated with walking and/or running should be simulated. Further, treadmill devices generally do not provide for upper limb motions normally associated with walking and/or running. Typically a user will place his/her hands on a stationary bar while walking/running on the treadmill. There exists, therefore, a need for an exercise machine which simulates natural motion of the upper limbs associated with walking and/or running.
Exercise machines may also be utilized for the training of athletes in the proper form for walking and/or running. Treadmills, however, do nothing to constrain the motions of the athlete's feet and/or hands. There exists, therefore, a need for an exercise machine for simulating walking and/or running motions while constraining the motions of the user's hands and/or feet to follow predetermined and well-defined paths.